Well, there's an odd thing about the situation, right? Normally, you play your character but you are not your character. So effectiveness is pretty much the only goal. Well, and style. What I'm saying is, if you increase intelligence it changes things about, say, how the character uses magic or what have you, but it doesn't change how well he makes plans or how cleverly he reacts to situations because that part is you, and your intelligence didn't change.
In his position I'd want to at least experiment with bumping intelligence just to see if I actually felt any smarter. His levels seem to be coming fairly fast, and he's hoping to live for a while. If intelligence really does make him smarter at thinking, his best bet might be to pump some Int right now so his judgement on how to improve later will be better . . .
Stats may be less important than abilities in the end. There are some serious badasses out there that use weird magic. Up to now, his abilities have been mainly physical--beating things down with a baseball bat, he's getting good at that. But no matter how good he gets at something like that, he might have trouble coping with some of the more subtle or freaky abilities out there. He's going to need to look into getting some kind of backup abilities . . . figure out what the opposition is likely to look like and what could counter their stuff.
Not that hitting things really hard is a bad ability. Very important one, actually. And he's got an energy bolt now too--nifty! He should totally keep doing that stuff.